/*
 * Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.nulldev.util.web.HttpServer3.util;

import java.util.Objects;
import java.util.Formatter;
import java.util.Locale;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;

/**
 * Prints formatted representations of objects to a text-output stream. This
 * class implements all of the <tt>print</tt> methods found in
 * {@link PrintStream}. It does not contain methods for writing raw bytes, for
 * which a program should use unencoded byte streams.
 *
 * <p>
 * Unlike the {@link PrintStream} class, if automatic flushing is enabled it
 * will be done only when one of the <tt>println</tt>, <tt>printf</tt>, or
 * <tt>format</tt> methods is invoked, rather than whenever a newline character
 * happens to be output. These methods use the platform's own notion of line
 * separator rather than the newline character.
 *
 * <p>
 * Methods in this class never throw I/O exceptions, although some of its
 * constructors may. The client may inquire as to whether any errors have
 * occurred by invoking {@link #checkError checkError()}.
 *
 * @author Frank Yellin
 * @author Mark Reinhold
 * @since JDK1.1
 */

public class HTTPPrintWriter extends Writer {

	private static final String HTTP_LINE_SEPERATOR = "\r\n";

	/**
	 * The underlying character-output stream of this <code>PrintWriter</code>.
	 *
	 * @since 1.2
	 */
	protected Writer out;

	private final boolean autoFlush;
	private boolean trouble = false;
	private Formatter formatter;
	private PrintStream psOut = null;

	/**
	 * Line separator string. This is the value of the line.separator property at
	 * the moment that the stream was created.
	 */
	private final String lineSeparator = HTTP_LINE_SEPERATOR;

	/**
	 * Returns a charset object for the given charset name.
	 * 
	 * @throws NullPointerException         is csn is null
	 * @throws UnsupportedEncodingException if the charset is not supported
	 */
	private static Charset toCharset(String csn) throws UnsupportedEncodingException {
		Objects.requireNonNull(csn, "charsetName");
		try {
			return Charset.forName(csn);
		} catch (IllegalCharsetNameException | UnsupportedCharsetException unused) {
			// UnsupportedEncodingException should be thrown
			throw new UnsupportedEncodingException(csn);
		}
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing.
	 *
	 * @param out A character-output stream
	 */
	public HTTPPrintWriter(Writer out) {
		this(out, false);
	}

	/**
	 * Creates a new PrintWriter.
	 *
	 * @param out       A character-output stream
	 * @param autoFlush A boolean; if true, the <tt>println</tt>, <tt>printf</tt>,
	 *                  or <tt>format</tt> methods will flush the output buffer
	 */
	public HTTPPrintWriter(Writer out, boolean autoFlush) {
		super(out);
		this.out = out;
		this.autoFlush = autoFlush;
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing, from an existing
	 * OutputStream. This convenience constructor creates the necessary intermediate
	 * OutputStreamWriter, which will convert characters into bytes using the
	 * default character encoding.
	 *
	 * @param out An output stream
	 *
	 * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
	 */
	public HTTPPrintWriter(OutputStream out) {
		this(out, false);
	}

	/**
	 * Creates a new PrintWriter from an existing OutputStream. This convenience
	 * constructor creates the necessary intermediate OutputStreamWriter, which will
	 * convert characters into bytes using the default character encoding.
	 *
	 * @param out       An output stream
	 * @param autoFlush A boolean; if true, the <tt>println</tt>, <tt>printf</tt>,
	 *                  or <tt>format</tt> methods will flush the output buffer
	 *
	 * @see java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
	 */
	public HTTPPrintWriter(OutputStream out, boolean autoFlush) {
		this(new BufferedWriter(new OutputStreamWriter(out)), autoFlush);

		// save print stream for error propagation
		if (out instanceof java.io.PrintStream) {
			psOut = (PrintStream) out;
		}
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing, with the
	 * specified file name. This convenience constructor creates the necessary
	 * intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which
	 * will encode characters using the
	 * {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for
	 * this instance of the Java virtual machine.
	 *
	 * @param fileName The name of the file to use as the destination of this
	 *                 writer. If the file exists then it will be truncated to zero
	 *                 size; otherwise, a new file will be created. The output will
	 *                 be written to the file and is buffered.
	 *
	 * @throws FileNotFoundException If the given string does not denote an
	 *                               existing, writable regular file and a new
	 *                               regular file of that name cannot be created, or
	 *                               if some other error occurs while opening or
	 *                               creating the file
	 *
	 * @throws SecurityException     If a security manager is present and
	 *                               {@link SecurityManager#checkWrite
	 *                               checkWrite(fileName)} denies write access to
	 *                               the file
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter(String fileName) throws FileNotFoundException {
		this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName))), false);
	}

	/* Private constructor */
	private HTTPPrintWriter(Charset charset, File file) throws FileNotFoundException {
		this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), charset)), false);
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing, with the
	 * specified file name and charset. This convenience constructor creates the
	 * necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter},
	 * which will encode characters using the provided charset.
	 *
	 * @param fileName The name of the file to use as the destination of this
	 *                 writer. If the file exists then it will be truncated to zero
	 *                 size; otherwise, a new file will be created. The output will
	 *                 be written to the file and is buffered.
	 *
	 * @param csn      The name of a supported {@linkplain java.nio.charset.Charset
	 *                 charset}
	 *
	 * @throws FileNotFoundException        If the given string does not denote an
	 *                                      existing, writable regular file and a
	 *                                      new regular file of that name cannot be
	 *                                      created, or if some other error occurs
	 *                                      while opening or creating the file
	 *
	 * @throws SecurityException            If a security manager is present and
	 *                                      {@link SecurityManager#checkWrite
	 *                                      checkWrite(fileName)} denies write
	 *                                      access to the file
	 *
	 * @throws UnsupportedEncodingException If the named charset is not supported
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException {
		this(toCharset(csn), new File(fileName));
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing, with the
	 * specified file. This convenience constructor creates the necessary
	 * intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, which
	 * will encode characters using the
	 * {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for
	 * this instance of the Java virtual machine.
	 *
	 * @param file The file to use as the destination of this writer. If the file
	 *             exists then it will be truncated to zero size; otherwise, a new
	 *             file will be created. The output will be written to the file and
	 *             is buffered.
	 *
	 * @throws FileNotFoundException If the given file object does not denote an
	 *                               existing, writable regular file and a new
	 *                               regular file of that name cannot be created, or
	 *                               if some other error occurs while opening or
	 *                               creating the file
	 *
	 * @throws SecurityException     If a security manager is present and
	 *                               {@link SecurityManager#checkWrite
	 *                               checkWrite(file.getPath())} denies write access
	 *                               to the file
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter(File file) throws FileNotFoundException {
		this(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file))), false);
	}

	/**
	 * Creates a new PrintWriter, without automatic line flushing, with the
	 * specified file and charset. This convenience constructor creates the
	 * necessary intermediate {@link java.io.OutputStreamWriter OutputStreamWriter},
	 * which will encode characters using the provided charset.
	 *
	 * @param file The file to use as the destination of this writer. If the file
	 *             exists then it will be truncated to zero size; otherwise, a new
	 *             file will be created. The output will be written to the file and
	 *             is buffered.
	 *
	 * @param csn  The name of a supported {@linkplain java.nio.charset.Charset
	 *             charset}
	 *
	 * @throws FileNotFoundException        If the given file object does not denote
	 *                                      an existing, writable regular file and a
	 *                                      new regular file of that name cannot be
	 *                                      created, or if some other error occurs
	 *                                      while opening or creating the file
	 *
	 * @throws SecurityException            If a security manager is present and
	 *                                      {@link SecurityManager#checkWrite
	 *                                      checkWrite(file.getPath())} denies write
	 *                                      access to the file
	 *
	 * @throws UnsupportedEncodingException If the named charset is not supported
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException {
		this(toCharset(csn), file);
	}

	/** Checks to make sure that the stream has not been closed */
	private void ensureOpen() throws IOException {
		if (out == null)
			throw new IOException("Stream closed");
	}

	/**
	 * Flushes the stream.
	 * 
	 * @see #checkError()
	 */
	public void flush() {
		try {
			synchronized (lock) {
				ensureOpen();
				out.flush();
			}
		} catch (IOException x) {
			trouble = true;
		}
	}

	/**
	 * Closes the stream and releases any system resources associated with it.
	 * Closing a previously closed stream has no effect.
	 *
	 * @see #checkError()
	 */
	public void close() {
		try {
			synchronized (lock) {
				if (out == null)
					return;
				out.close();
				out = null;
			}
		} catch (IOException x) {
			trouble = true;
		}
	}

	/**
	 * Flushes the stream if it's not closed and checks its error state.
	 *
	 * @return <code>true</code> if the print stream has encountered an error,
	 *         either on the underlying output stream or during a format conversion.
	 */
	public boolean checkError() {
		if (out != null) {
			flush();
		}
		if (out instanceof java.io.PrintWriter) {
			HTTPPrintWriter pw = (HTTPPrintWriter) out;
			return pw.checkError();
		} else if (psOut != null) {
			return psOut.checkError();
		}
		return trouble;
	}

	/**
	 * Indicates that an error has occurred.
	 *
	 * <p>
	 * This method will cause subsequent invocations of {@link #checkError()} to
	 * return <tt>true</tt> until {@link #clearError()} is invoked.
	 */
	protected void setError() {
		trouble = true;
	}

	/**
	 * Clears the error state of this stream.
	 *
	 * <p>
	 * This method will cause subsequent invocations of {@link #checkError()} to
	 * return <tt>false</tt> until another write operation fails and invokes
	 * {@link #setError()}.
	 *
	 * @since 1.6
	 */
	protected void clearError() {
		trouble = false;
	}

	/*
	 * Exception-catching, synchronized output operations, which also implement the
	 * write() methods of Writer
	 */

	/**
	 * Writes a single character.
	 * 
	 * @param c int specifying a character to be written.
	 */
	public void write(int c) {
		try {
			synchronized (lock) {
				ensureOpen();
				out.write(c);
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
	}

	/**
	 * Writes A Portion of an array of characters.
	 * 
	 * @param buf Array of characters
	 * @param off Offset from which to start writing characters
	 * @param len Number of characters to write
	 */
	public void write(char buf[], int off, int len) {
		try {
			synchronized (lock) {
				ensureOpen();
				out.write(buf, off, len);
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
	}

	/**
	 * Writes an array of characters. This method cannot be inherited from the
	 * Writer class because it must suppress I/O exceptions.
	 * 
	 * @param buf Array of characters to be written
	 */
	public void write(char buf[]) {
		write(buf, 0, buf.length);
	}

	/**
	 * Writes a portion of a string.
	 * 
	 * @param s   A String
	 * @param off Offset from which to start writing characters
	 * @param len Number of characters to write
	 */
	public void write(String s, int off, int len) {
		try {
			synchronized (lock) {
				ensureOpen();
				out.write(s, off, len);
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
	}

	/**
	 * Writes a string. This method cannot be inherited from the Writer class
	 * because it must suppress I/O exceptions.
	 * 
	 * @param s String to be written
	 */
	public void write(String s) {
		write(s, 0, s.length());
	}

	private void newLine() {
		try {
			synchronized (lock) {
				ensureOpen();
				out.write(lineSeparator);
				if (autoFlush)
					out.flush();
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
	}

	/* Methods that do not terminate lines */

	/**
	 * Prints a boolean value. The string produced by <code>{@link
	 * java.lang.String#valueOf(boolean)}</code> is translated into bytes according
	 * to the platform's default character encoding, and these bytes are written in
	 * exactly the manner of the <code>{@link
	 * #write(int)}</code> method.
	 *
	 * @param b The <code>boolean</code> to be printed
	 */
	public void print(boolean b) {
		write(b ? "true" : "false");
	}

	/**
	 * Prints a character. The character is translated into one or more bytes
	 * according to the platform's default character encoding, and these bytes are
	 * written in exactly the manner of the <code>{@link
	 * #write(int)}</code> method.
	 *
	 * @param c The <code>char</code> to be printed
	 */
	public void print(char c) {
		write(c);
	}

	/**
	 * Prints an integer. The string produced by <code>{@link
	 * java.lang.String#valueOf(int)}</code> is translated into bytes according to
	 * the platform's default character encoding, and these bytes are written in
	 * exactly the manner of the <code>{@link #write(int)}</code> method.
	 *
	 * @param i The <code>int</code> to be printed
	 * @see java.lang.Integer#toString(int)
	 */
	public void print(int i) {
		write(String.valueOf(i));
	}

	/**
	 * Prints a long integer. The string produced by <code>{@link
	 * java.lang.String#valueOf(long)}</code> is translated into bytes according to
	 * the platform's default character encoding, and these bytes are written in
	 * exactly the manner of the <code>{@link #write(int)}</code> method.
	 *
	 * @param l The <code>long</code> to be printed
	 * @see java.lang.Long#toString(long)
	 */
	public void print(long l) {
		write(String.valueOf(l));
	}

	/**
	 * Prints a floating-point number. The string produced by <code>{@link
	 * java.lang.String#valueOf(float)}</code> is translated into bytes according to
	 * the platform's default character encoding, and these bytes are written in
	 * exactly the manner of the <code>{@link #write(int)}</code> method.
	 *
	 * @param f The <code>float</code> to be printed
	 * @see java.lang.Float#toString(float)
	 */
	public void print(float f) {
		write(String.valueOf(f));
	}

	/**
	 * Prints a double-precision floating-point number. The string produced by
	 * <code>{@link java.lang.String#valueOf(double)}</code> is translated into
	 * bytes according to the platform's default character encoding, and these bytes
	 * are written in exactly the manner of the <code>{@link
	 * #write(int)}</code> method.
	 *
	 * @param d The <code>double</code> to be printed
	 * @see java.lang.Double#toString(double)
	 */
	public void print(double d) {
		write(String.valueOf(d));
	}

	/**
	 * Prints an array of characters. The characters are converted into bytes
	 * according to the platform's default character encoding, and these bytes are
	 * written in exactly the manner of the <code>{@link #write(int)}</code> method.
	 *
	 * @param s The array of chars to be printed
	 *
	 * @throws NullPointerException If <code>s</code> is <code>null</code>
	 */
	public void print(char s[]) {
		write(s);
	}

	/**
	 * Prints a string. If the argument is <code>null</code> then the string
	 * <code>"null"</code> is printed. Otherwise, the string's characters are
	 * converted into bytes according to the platform's default character encoding,
	 * and these bytes are written in exactly the manner of the
	 * <code>{@link #write(int)}</code> method.
	 *
	 * @param s The <code>String</code> to be printed
	 */
	public void print(String s) {
		if (s == null) {
			s = "null";
		}
		write(s);
	}

	/**
	 * Prints an object. The string produced by the <code>{@link
	 * java.lang.String#valueOf(Object)}</code> method is translated into bytes
	 * according to the platform's default character encoding, and these bytes are
	 * written in exactly the manner of the <code>{@link #write(int)}</code> method.
	 *
	 * @param obj The <code>Object</code> to be printed
	 * @see java.lang.Object#toString()
	 */
	public void print(Object obj) {
		write(String.valueOf(obj));
	}

	/* Methods that do terminate lines */

	/**
	 * Terminates the current line by writing the line separator string. The line
	 * separator string is defined by the system property
	 * <code>line.separator</code>, and is not necessarily a single newline
	 * character (<code>'\n'</code>).
	 */
	public void println() {
		newLine();
	}

	/**
	 * Prints a boolean value and then terminates the line. This method behaves as
	 * though it invokes <code>{@link #print(boolean)}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x the <code>boolean</code> value to be printed
	 */
	public void println(boolean x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints a character and then terminates the line. This method behaves as
	 * though it invokes <code>{@link #print(char)}</code> and then <code>{@link
	 * #println()}</code>.
	 *
	 * @param x the <code>char</code> value to be printed
	 */
	public void println(char x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints an integer and then terminates the line. This method behaves as though
	 * it invokes <code>{@link #print(int)}</code> and then <code>{@link
	 * #println()}</code>.
	 *
	 * @param x the <code>int</code> value to be printed
	 */
	public void println(int x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints a long integer and then terminates the line. This method behaves as
	 * though it invokes <code>{@link #print(long)}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x the <code>long</code> value to be printed
	 */
	public void println(long x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints a floating-point number and then terminates the line. This method
	 * behaves as though it invokes <code>{@link #print(float)}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x the <code>float</code> value to be printed
	 */
	public void println(float x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints a double-precision floating-point number and then terminates the line.
	 * This method behaves as though it invokes <code>{@link
	 * #print(double)}</code> and then <code>{@link #println()}</code>.
	 *
	 * @param x the <code>double</code> value to be printed
	 */
	public void println(double x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints an array of characters and then terminates the line. This method
	 * behaves as though it invokes <code>{@link #print(char[])}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x the array of <code>char</code> values to be printed
	 */
	public void println(char x[]) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints a String and then terminates the line. This method behaves as though
	 * it invokes <code>{@link #print(String)}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x the <code>String</code> value to be printed
	 */
	public void println(String x) {
		synchronized (lock) {
			print(x);
			println();
		}
	}

	/**
	 * Prints an Object and then terminates the line. This method calls at first
	 * String.valueOf(x) to get the printed object's string value, then behaves as
	 * though it invokes <code>{@link #print(String)}</code> and then
	 * <code>{@link #println()}</code>.
	 *
	 * @param x The <code>Object</code> to be printed.
	 */
	public void println(Object x) {
		String s = String.valueOf(x);
		synchronized (lock) {
			print(s);
			println();
		}
	}

	/**
	 * A convenience method to write a formatted string to this writer using the
	 * specified format string and arguments. If automatic flushing is enabled,
	 * calls to this method will flush the output buffer.
	 *
	 * <p>
	 * An invocation of this method of the form <tt>out.printf(format,
	 * args)</tt> behaves in exactly the same way as the invocation
	 *
	 * <pre>
	 * out.format(format, args)
	 * </pre>
	 *
	 * @param format A format string as described in
	 *               <a href="../util/Formatter.html#syntax">Format string
	 *               syntax</a>.
	 *
	 * @param args   Arguments referenced by the format specifiers in the format
	 *               string. If there are more arguments than format specifiers, the
	 *               extra arguments are ignored. The number of arguments is
	 *               variable and may be zero. The maximum number of arguments is
	 *               limited by the maximum dimension of a Java array as defined by
	 *               <cite>The Java&trade; Virtual Machine Specification</cite>. The
	 *               behaviour on a <tt>null</tt> argument depends on the
	 *               <a href="../util/Formatter.html#syntax">conversion</a>.
	 *
	 * @throws java.util.IllegalFormatException If a format string contains an
	 *                                          illegal syntax, a format specifier
	 *                                          that is incompatible with the given
	 *                                          arguments, insufficient arguments
	 *                                          given the format string, or other
	 *                                          illegal conditions. For
	 *                                          specification of all possible
	 *                                          formatting errors, see the <a href=
	 *                                          "../util/Formatter.html#detail">Details</a>
	 *                                          section of the formatter class
	 *                                          specification.
	 *
	 * @throws NullPointerException             If the <tt>format</tt> is
	 *                                          <tt>null</tt>
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter printf(String format, Object... args) {
		return format(format, args);
	}

	/**
	 * A convenience method to write a formatted string to this writer using the
	 * specified format string and arguments. If automatic flushing is enabled,
	 * calls to this method will flush the output buffer.
	 *
	 * <p>
	 * An invocation of this method of the form <tt>out.printf(l, format,
	 * args)</tt> behaves in exactly the same way as the invocation
	 *
	 * <pre>
	 * out.format(l, format, args)
	 * </pre>
	 *
	 * @param l      The {@linkplain java.util.Locale locale} to apply during
	 *               formatting. If <tt>l</tt> is <tt>null</tt> then no localization
	 *               is applied.
	 *
	 * @param format A format string as described in
	 *               <a href="../util/Formatter.html#syntax">Format string
	 *               syntax</a>.
	 *
	 * @param args   Arguments referenced by the format specifiers in the format
	 *               string. If there are more arguments than format specifiers, the
	 *               extra arguments are ignored. The number of arguments is
	 *               variable and may be zero. The maximum number of arguments is
	 *               limited by the maximum dimension of a Java array as defined by
	 *               <cite>The Java&trade; Virtual Machine Specification</cite>. The
	 *               behaviour on a <tt>null</tt> argument depends on the
	 *               <a href="../util/Formatter.html#syntax">conversion</a>.
	 *
	 * @throws java.util.IllegalFormatException If a format string contains an
	 *                                          illegal syntax, a format specifier
	 *                                          that is incompatible with the given
	 *                                          arguments, insufficient arguments
	 *                                          given the format string, or other
	 *                                          illegal conditions. For
	 *                                          specification of all possible
	 *                                          formatting errors, see the <a href=
	 *                                          "../util/Formatter.html#detail">Details</a>
	 *                                          section of the formatter class
	 *                                          specification.
	 *
	 * @throws NullPointerException             If the <tt>format</tt> is
	 *                                          <tt>null</tt>
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter printf(Locale l, String format, Object... args) {
		return format(l, format, args);
	}

	/**
	 * Writes a formatted string to this writer using the specified format string
	 * and arguments. If automatic flushing is enabled, calls to this method will
	 * flush the output buffer.
	 *
	 * <p>
	 * The locale always used is the one returned by
	 * {@link java.util.Locale#getDefault() Locale.getDefault()}, regardless of any
	 * previous invocations of other formatting methods on this object.
	 *
	 * @param format A format string as described in
	 *               <a href="../util/Formatter.html#syntax">Format string
	 *               syntax</a>.
	 *
	 * @param args   Arguments referenced by the format specifiers in the format
	 *               string. If there are more arguments than format specifiers, the
	 *               extra arguments are ignored. The number of arguments is
	 *               variable and may be zero. The maximum number of arguments is
	 *               limited by the maximum dimension of a Java array as defined by
	 *               <cite>The Java&trade; Virtual Machine Specification</cite>. The
	 *               behaviour on a <tt>null</tt> argument depends on the
	 *               <a href="../util/Formatter.html#syntax">conversion</a>.
	 *
	 * @throws java.util.IllegalFormatException If a format string contains an
	 *                                          illegal syntax, a format specifier
	 *                                          that is incompatible with the given
	 *                                          arguments, insufficient arguments
	 *                                          given the format string, or other
	 *                                          illegal conditions. For
	 *                                          specification of all possible
	 *                                          formatting errors, see the <a href=
	 *                                          "../util/Formatter.html#detail">Details</a>
	 *                                          section of the Formatter class
	 *                                          specification.
	 *
	 * @throws NullPointerException             If the <tt>format</tt> is
	 *                                          <tt>null</tt>
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter format(String format, Object... args) {
		try {
			synchronized (lock) {
				ensureOpen();
				if ((formatter == null) || (formatter.locale() != Locale.getDefault()))
					formatter = new Formatter(this);
				formatter.format(Locale.getDefault(), format, args);
				if (autoFlush)
					out.flush();
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
		return this;
	}

	/**
	 * Writes a formatted string to this writer using the specified format string
	 * and arguments. If automatic flushing is enabled, calls to this method will
	 * flush the output buffer.
	 *
	 * @param l      The {@linkplain java.util.Locale locale} to apply during
	 *               formatting. If <tt>l</tt> is <tt>null</tt> then no localization
	 *               is applied.
	 *
	 * @param format A format string as described in
	 *               <a href="../util/Formatter.html#syntax">Format string
	 *               syntax</a>.
	 *
	 * @param args   Arguments referenced by the format specifiers in the format
	 *               string. If there are more arguments than format specifiers, the
	 *               extra arguments are ignored. The number of arguments is
	 *               variable and may be zero. The maximum number of arguments is
	 *               limited by the maximum dimension of a Java array as defined by
	 *               <cite>The Java&trade; Virtual Machine Specification</cite>. The
	 *               behaviour on a <tt>null</tt> argument depends on the
	 *               <a href="../util/Formatter.html#syntax">conversion</a>.
	 *
	 * @throws java.util.IllegalFormatException If a format string contains an
	 *                                          illegal syntax, a format specifier
	 *                                          that is incompatible with the given
	 *                                          arguments, insufficient arguments
	 *                                          given the format string, or other
	 *                                          illegal conditions. For
	 *                                          specification of all possible
	 *                                          formatting errors, see the <a href=
	 *                                          "../util/Formatter.html#detail">Details</a>
	 *                                          section of the formatter class
	 *                                          specification.
	 *
	 * @throws NullPointerException             If the <tt>format</tt> is
	 *                                          <tt>null</tt>
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter format(Locale l, String format, Object... args) {
		try {
			synchronized (lock) {
				ensureOpen();
				if ((formatter == null) || (formatter.locale() != l))
					formatter = new Formatter(this, l);
				formatter.format(l, format, args);
				if (autoFlush)
					out.flush();
			}
		} catch (InterruptedIOException x) {
			Thread.currentThread().interrupt();
		} catch (IOException x) {
			trouble = true;
		}
		return this;
	}

	/**
	 * Appends the specified character sequence to this writer.
	 *
	 * <p>
	 * An invocation of this method of the form <tt>out.append(csq)</tt> behaves in
	 * exactly the same way as the invocation
	 *
	 * <pre>
	 * out.write(csq.toString())
	 * </pre>
	 *
	 * <p>
	 * Depending on the specification of <tt>toString</tt> for the character
	 * sequence <tt>csq</tt>, the entire sequence may not be appended. For instance,
	 * invoking the <tt>toString</tt> method of a character buffer will return a
	 * subsequence whose content depends upon the buffer's position and limit.
	 *
	 * @param csq The character sequence to append. If <tt>csq</tt> is
	 *            <tt>null</tt>, then the four characters <tt>"null"</tt> are
	 *            appended to this writer.
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter append(CharSequence csq) {
		if (csq == null)
			write("null");
		else
			write(csq.toString());
		return this;
	}

	/**
	 * Appends a subsequence of the specified character sequence to this writer.
	 *
	 * <p>
	 * An invocation of this method of the form <tt>out.append(csq, start,
	 * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in exactly the same
	 * way as the invocation
	 *
	 * <pre>
	 * out.write(csq.subSequence(start, end).toString())
	 * </pre>
	 *
	 * @param csq   The character sequence from which a subsequence will be
	 *              appended. If <tt>csq</tt> is <tt>null</tt>, then characters will
	 *              be appended as if <tt>csq</tt> contained the four characters
	 *              <tt>"null"</tt>.
	 *
	 * @param start The index of the first character in the subsequence
	 *
	 * @param end   The index of the character following the last character in the
	 *              subsequence
	 *
	 * @return This writer
	 *
	 * @throws IndexOutOfBoundsException If <tt>start</tt> or <tt>end</tt> are
	 *                                   negative, <tt>start</tt> is greater than
	 *                                   <tt>end</tt>, or <tt>end</tt> is greater
	 *                                   than <tt>csq.length()</tt>
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter append(CharSequence csq, int start, int end) {
		CharSequence cs = (csq == null ? "null" : csq);
		write(cs.subSequence(start, end).toString());
		return this;
	}

	/**
	 * Appends the specified character to this writer.
	 *
	 * <p>
	 * An invocation of this method of the form <tt>out.append(c)</tt> behaves in
	 * exactly the same way as the invocation
	 *
	 * <pre>
	 * out.write(c)
	 * </pre>
	 *
	 * @param c The 16-bit character to append
	 *
	 * @return This writer
	 *
	 * @since 1.5
	 */
	public HTTPPrintWriter append(char c) {
		write(c);
		return this;
	}
}
